NEW YORK (CNNMoney.com) -- For months, we've fretted about the Armageddon that will hit when subprime adjustable rate mortgages start resetting to much higher interest rates.

What's happening is even worse: Many of these loans are defaulting well before their rates increase.

Defaults for subprime loans issued in 2007 - none of which have reset yet - hit 11.2 percent in November. That represents perhaps 300,000 households, and istwice the default rate that 2006 loans had 10 months after being issued, according to Friedman, Billings Ramsey analyst Michael Youngblood.

Defaults are spiking well before resets come into play thanks to the lax lending environment of the past few years. Many borrowers were approved for mortgages that they had little chance of affording, even at the low-interest teaser rates .

"I was rather shocked by the characteristics of the 2007 loans," said Youngblood.

Hybrid ARMs start with very affordable fixed-rate terms of two or three years. After that, rates can jump three percentage points or more, and then re-adjust even higher every six months to a year. On a $200,000 mortgage, a reset could add nearly $400 to the monthly mortgage payment.

Originally, concerns about these loans focused on the fact that that most homeowners wouldn't survive such pricey resets. In late 2006, the Center for Responsible Lending (CRL), predicted that 2.2 million subprime ARM borrowers would lose their homes in the following two years due to reset shock.

But these mortgages were doomed from the start.

For instance, in both 2006 and 2007, well over 40 percent of subprime borrowers were awarded mortgages with either little or no documentation of their ability to pay. With these so-called "liar loans," borrowers did not have to show proof of either earnings or assets.

And even when borrowers did go on the record about their earning power, it didn't bode well. Both 2006 and 2007 saw a large proportion of loans with high debt-to-income ratios (DTI), which indicates the percentage of gross income required to pay debt. In 2007 subprime originations, the DTI hit 42.1 percent, up from 41.1 percent in 2006. Borrowers were simply taking on more debt that they could afford.

What's more, many borrowers started out with low- or no-down payment loans, which left them with almost no equity in their home.

During the boom, rapid price appreciation meant borrowers built up home equity quickly. That minimized defaults, since owners could draw from that equity to pay their bills - including their mortgages - through home equity loans.

By late 2006, lenders knew that the housing market was heading south. Foreclosure filings took off during the third quarter that year, up 43 percent from 12 months earlier, according to RealtyTrac, the online marketer of foreclosure properties. And home prices began to drop.

But instead of cutting back on risky loans, lenders kept lending. Why?

"Because investors continued to buy the loans," said Doug Duncan, chief economist of the Mortgage Bankers Association.

Despite their quality, subprime mortgages were as profitable as any other for lenders like Countrywide (CFC, Fortune 500) and Wells Fargo (WFC, Fortune 500), who were able to quickly securitize the loans and sell them in the secondary market. The loans sold easily because they carried the promise of high yields.

"As long as you could sell the loan, you made the deal," Duncan said.

Lenders needed the fees that these loans generated because their finances were weakening. Their cost of borrowing money was rising, while competitive pressures were keeping mortgage interest rates low.

"By 2006 many lenders were running into red ink," said Youngblood.

So, they revved up lending to increase short-term profits. And, to outside analysts, there appeared to be nothing wrong with loan quality.

"There were very few overt changes in industry underwriting guidelines," said Youngblood. What did change, he said, was that lenders made more exceptions to their standard practices, approving people with poor work histories or insufficient proof of income.

"These exceptions generally amounted to no more than 5 percent [of subprime loans] before 2006," said Youngblood, "but they represented the majority of these loans issued in 2006 and 2007."

The reason for that shift: Lenders depended on independent mortgage brokers for much of their business, and brokers pushed them to approve subprime loans because they delivered big profits for the brokers.

"Lenders felt they had to take the loans to preserve their access [to the rest of the loan pool]," he said. They accepted some risky subprime loans so that the brokers would also send them safer prime and Alt-A loans.

Of course that's a bet that went bad. And it's likely to get worse as resets for ARMs issued in 2006 and 2007 kick in this year.